David M Clifford

US Patent:

56025181, Feb 11, 1997

Filed:

Mar 24, 1995

Appl. No.:

8/410024

Inventors:

David G. Clifford - Albuquerque NM
Brian C. Walker - Albuquerque NM

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H01P 1205

US Classification:

333202

Abstract:

A ceramic filter (120) with at least one transmission zero is disclosed. The filter (120) has a filter body comprising a block of dielectric material and having top (110), bottom (112), and side surfaces, and having metallized through-holes extending from the top to the bottom surfaces defining resonators. The surfaces are substantially covered with a conductive material defining a metallized layer. The top surface (110) is uncoated. The filter (120) can also include input-output pads ( 104, 106). The bottom surface (112) has a channel (108) defining a magnetic coupling between the resonators. The channel configuration and placement can vary depending on the desired frequency response.

US Patent:

57215200, Feb 24, 1998

Filed:

Aug 14, 1995

Appl. No.:

8/514581

Inventors:

Thomas G. McVeety - Albuquerque NM
David G. Clifford - Albuquerque NM

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H01P 120

US Classification:

333202

Abstract:

A ceramic filter (10) is shown and described. The filter (10) has a filter body having top (14), bottom (16), and side surfaces (18, 20, 22 and 24) with through holes (26, 28) extending from the top (14) to the bottom surfaces (16) defining resonators. The surfaces are substantially covered with a conductive material defining a metallized layer, with the exception that the top surface (14) is substantially uncoated, and with an additional exception that a portion of a side surface is substantially uncoated in proximity to the top surface (14) and extending at least in proximity to between the resonators (26, 28), defining an unmetallized coupling region for electrically coupling the resonators. The filter (10) also has first and second input-output pads (34, 38) on a side surface for facilitating connection to a circuit board, for example.

US Patent:

54366020, Jul 25, 1995

Filed:

Apr 28, 1994

Appl. No.:

8/234339

Inventors:

Thomas McVeety - Albuquerque NM
David G. Clifford - Albuquerque NM

International Classification:

H01P 1205

US Classification:

333206

Abstract:

A ceramic filter with a high side transmission zero. The ceramic filter (10) has: a filter body (12) of a dielectric material having top, bottom and side surfaces (14, 16, 18, 20, 22, 24). Two through-holes extending from the top (14) to the bottom surface (16), defining resonators (26,28) are included. The surfaces are substantially covered with a conductive material, defining a metallized layer (30), with the exception that the top surface (14) is substantially uncoated and with the additional exception that a portion of the side surface is also uncoated (32) in proximity to the bottom surface (16), and it extends laterally at least in proximity to the resonators (26,28), defining a magnetic transmission line (32) for magnetically coupling the resonators (26,28). Surface mountable first and second input-output pads (34,38) are also provided.

US Patent:

48003484, Jan 24, 1989

Filed:

Aug 3, 1987

Appl. No.:

7/081264

Inventors:

George C. Rosar - Waseca MN
David G. Clifford - Albuquerque NM

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H01P 1205
H01P 704

US Classification:

333202

Abstract:

An adjustable electronic filter apparatus is disclosed comprising a dielectric block having one or more through-holes and having a conformal conductive coating substantially over all outside surfaces as well as each through-hole therein. Each through-hole so plated forms a resonator from a transmission line which includes an open portion, for providing capacitive reactance at a first end, and a short-circuited end as a base, for providing an associated distributed inductance at a second end thereof. A unique method of tuning the adjustable electronic filter, whether a single resonator, a plurality of resonators, or a plurality of intercoupled multi-resonator filters, is disclosed that permits bi-directional tuning for at least one resonator in each of the above exemplary embodiments. By selectively adjusting an inductive portion of the plating at the base of each resonator so tuned, a resonator is quickly and accurately adjusted to a desired frequency. The selective adjusting may be accomplished by subtractive processes, such as abrasion or laser trimming, or by an additive process, such as by adding conductive paint for partially filling in a removed or absent portion of the plating at the base of a resonator.

US Patent:

20170263096, Sep 14, 2017

Filed:

Mar 14, 2016

Appl. No.:

15/068720

Inventors:

David G. Clifford - Albuquerque NM, US

International Classification:

G08B 21/02
G08B 15/02
H04W 4/22
H04B 1/3827
H04B 7/155

Abstract:

Disclosed is a Crime on Campus Neutralization System comprising a communication network of 2-way radios connecting a USER to a USER-REPEATER, subsequently to a LINK-REPEATER, enabling a USER to ultimately initiate a LOCK-DOWN procedure on a CAMPUS. Further disclosed, here within, are methods that enable the system to work effectively. This system is very cost effective, consisting of components that can be bought off the shelf. The system is unique in that it does not use the internet, a cell-phone device, a tablet, a computer, or any other device that, by its design, could be “hacked” or “compromised” by outside parties. The system is not complex, unlike other systems which rely on extensive software programs, but instead relies on a 6 decade proven technology.